The US President described the deaths of 298 people as a tragedy of “unspeakable proportions” and insisted there must be a full independent criminal inquiry.

Mr Obama told Putin it was time for him to step in and stop the violence in the war-torn eastern Ukraine.

He spoke as foreign investigators were allowed access to the crash scene and amid claims one of the plane’s black boxes had been smuggled to Russia.

In a strong message to Putin, Mr Obama said: “We don’t have time for propaganda. We don’t have time for games. When terrible events like this occur, the international community must stand on the side of justice.”

The spy boss said: “The most important thing is the last names of all three members of the crew who directly controlled the Buk SAM and who directly pulled the trigger.”

Britain’s Ambassador to the United Nations Mark Lyall Grant pointed the finger at the rebels and their Russian backers at an emergency Security Council session called by the UK.

He said: “It is clear where responsibility lies – with the senseless violence of armed separatists and with those who support, equip and advise them.”

Mr Nalyvaichenko also saod two other Russian soldiers had been arrested and claimed the weapons system which downed the plane was Russian.

He claimed both arrested men had Russian passports “and one of them was so clever that he brought his army tickets with him where his army job is written – target spotter.”

Interior Minister Arsen Avakov added: “Surveillance units of the Ukrainian Interior Ministry at 0450 recorded a tow vehicle with a tracked missile system loaded on it moving in the direction of the Russian border.

“The video recording shows uncovered missiles. Two missiles are there but the middle one is nowhere to be seen.”

It is thought Russia’s GRU military intelligence agency dispatched a small team to the crash site to find one of the boxes.

Although it will give away little information on a missile attack, it may arm Putin with details of the tragedy ahead of the investigation. It could also aid the Russian leader with information to help him deny his forces had any involvement.

A source told The Daily Mirror: “One of the black boxes is rumoured to have been has secreted back to Moscow.

“The investigators took a few hours to get to the crash site so the separatists accused of causing it had time to search out one of the black boxes.”

Today Prime Minister David Cameron stopped short of blaming the separatist forces after holding crisis talks with the security service chiefs and senior Cabinet ministers. But more evidence implicating them emerged during the day.

PA

Cautious: PM Cameron

Ukrainian PM Arseniy Yatsenyuk blasted it as an “international crime against humanity”.

He added: “Yesterday’s terrible tragedy will change our lives. The Russians have done it now.”

He urged the international community “to support the Ukrainian government to bring to justice those b*****ds who committed this international crime.”

Ukraine’s President Petro Proshenko added: “Shooting down a civilian aircraft is an act of international terrorism targeted against the entire world.

"This is a wake-up call for the whole world. We expect an adequate response from the international community.

“For weeks we have shed tears over our own dead. We have tears left for the innocent victims of this crime. Today Ukraine mourns with you.”

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Outraged: Mrs Clinton is putting pressure on Putin

Former US secretary of state Hillary Clinton called for European leaders to put more pressure on Putin.

She said there should be “outrage in European capitals” over Russian aggression in the region but ultimately it was up to Europe to take the lead.

She endorsed stepped-up US sanctions against Russia but said they would not “necessarily restrain” Mr Putin.

Angry Australian prime minister Tony Abbott also demanded an independent inquiry, adding: “The initial response of the Russian ambassador was to blame Ukraine for this and I have to say that is deeply, deeply unsatisfactory.”